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<h1 id="sec_name">
<span data-if="hdevelop" style="display:inline;">points_sojka</span><span data-if="c" style="display:none;">T_points_sojka</span><span data-if="cpp" style="display:none;">PointsSojka</span><span data-if="dotnet" style="display:none;">PointsSojka</span><span data-if="python" style="display:none;">points_sojka</span> (算子名称)</h1>
<h2>名称</h2>
<p><code><span data-if="hdevelop" style="display:inline;">points_sojka</span><span data-if="c" style="display:none;">T_points_sojka</span><span data-if="cpp" style="display:none;">PointsSojka</span><span data-if="dotnet" style="display:none;">PointsSojka</span><span data-if="python" style="display:none;">points_sojka</span></code> — Find corners using the Sojka operator.</p>
<h2 id="sec_synopsis">参数签名</h2>
<div data-if="hdevelop" style="display:inline;">
<p>
<code><b>points_sojka</b>(<a href="#Image"><i>Image</i></a> :  : <a href="#MaskSize"><i>MaskSize</i></a>, <a href="#SigmaW"><i>SigmaW</i></a>, <a href="#SigmaD"><i>SigmaD</i></a>, <a href="#MinGrad"><i>MinGrad</i></a>, <a href="#MinApparentness"><i>MinApparentness</i></a>, <a href="#MinAngle"><i>MinAngle</i></a>, <a href="#Subpix"><i>Subpix</i></a> : <a href="#Row"><i>Row</i></a>, <a href="#Column"><i>Column</i></a>)</code></p>
</div>
<div data-if="c" style="display:none;">
<p>
<code>Herror <b>T_points_sojka</b>(const Hobject <a href="#Image"><i>Image</i></a>, const Htuple <a href="#MaskSize"><i>MaskSize</i></a>, const Htuple <a href="#SigmaW"><i>SigmaW</i></a>, const Htuple <a href="#SigmaD"><i>SigmaD</i></a>, const Htuple <a href="#MinGrad"><i>MinGrad</i></a>, const Htuple <a href="#MinApparentness"><i>MinApparentness</i></a>, const Htuple <a href="#MinAngle"><i>MinAngle</i></a>, const Htuple <a href="#Subpix"><i>Subpix</i></a>, Htuple* <a href="#Row"><i>Row</i></a>, Htuple* <a href="#Column"><i>Column</i></a>)</code></p>
</div>
<div data-if="cpp" style="display:none;">
<p>
<code>void <b>PointsSojka</b>(const HObject&amp; <a href="#Image"><i>Image</i></a>, const HTuple&amp; <a href="#MaskSize"><i>MaskSize</i></a>, const HTuple&amp; <a href="#SigmaW"><i>SigmaW</i></a>, const HTuple&amp; <a href="#SigmaD"><i>SigmaD</i></a>, const HTuple&amp; <a href="#MinGrad"><i>MinGrad</i></a>, const HTuple&amp; <a href="#MinApparentness"><i>MinApparentness</i></a>, const HTuple&amp; <a href="#MinAngle"><i>MinAngle</i></a>, const HTuple&amp; <a href="#Subpix"><i>Subpix</i></a>, HTuple* <a href="#Row"><i>Row</i></a>, HTuple* <a href="#Column"><i>Column</i></a>)</code></p>
<p>
<code>void <a href="HImage.html">HImage</a>::<b>PointsSojka</b>(Hlong <a href="#MaskSize"><i>MaskSize</i></a>, const HTuple&amp; <a href="#SigmaW"><i>SigmaW</i></a>, const HTuple&amp; <a href="#SigmaD"><i>SigmaD</i></a>, const HTuple&amp; <a href="#MinGrad"><i>MinGrad</i></a>, const HTuple&amp; <a href="#MinApparentness"><i>MinApparentness</i></a>, double <a href="#MinAngle"><i>MinAngle</i></a>, const HString&amp; <a href="#Subpix"><i>Subpix</i></a>, HTuple* <a href="#Row"><i>Row</i></a>, HTuple* <a href="#Column"><i>Column</i></a>) const</code></p>
<p>
<code>void <a href="HImage.html">HImage</a>::<b>PointsSojka</b>(Hlong <a href="#MaskSize"><i>MaskSize</i></a>, double <a href="#SigmaW"><i>SigmaW</i></a>, double <a href="#SigmaD"><i>SigmaD</i></a>, double <a href="#MinGrad"><i>MinGrad</i></a>, double <a href="#MinApparentness"><i>MinApparentness</i></a>, double <a href="#MinAngle"><i>MinAngle</i></a>, const HString&amp; <a href="#Subpix"><i>Subpix</i></a>, HTuple* <a href="#Row"><i>Row</i></a>, HTuple* <a href="#Column"><i>Column</i></a>) const</code></p>
<p>
<code>void <a href="HImage.html">HImage</a>::<b>PointsSojka</b>(Hlong <a href="#MaskSize"><i>MaskSize</i></a>, double <a href="#SigmaW"><i>SigmaW</i></a>, double <a href="#SigmaD"><i>SigmaD</i></a>, double <a href="#MinGrad"><i>MinGrad</i></a>, double <a href="#MinApparentness"><i>MinApparentness</i></a>, double <a href="#MinAngle"><i>MinAngle</i></a>, const char* <a href="#Subpix"><i>Subpix</i></a>, HTuple* <a href="#Row"><i>Row</i></a>, HTuple* <a href="#Column"><i>Column</i></a>) const</code></p>
<p>
<code>void <a href="HImage.html">HImage</a>::<b>PointsSojka</b>(Hlong <a href="#MaskSize"><i>MaskSize</i></a>, double <a href="#SigmaW"><i>SigmaW</i></a>, double <a href="#SigmaD"><i>SigmaD</i></a>, double <a href="#MinGrad"><i>MinGrad</i></a>, double <a href="#MinApparentness"><i>MinApparentness</i></a>, double <a href="#MinAngle"><i>MinAngle</i></a>, const wchar_t* <a href="#Subpix"><i>Subpix</i></a>, HTuple* <a href="#Row"><i>Row</i></a>, HTuple* <a href="#Column"><i>Column</i></a>) const  <span class="signnote">
            (
            Windows only)
          </span></code></p>
</div>
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<div data-if="dotnet" style="display:none;">
<p>
<code>static void <a href="HOperatorSet.html">HOperatorSet</a>.<b>PointsSojka</b>(<a href="HObject.html">HObject</a> <a href="#Image"><i>image</i></a>, <a href="HTuple.html">HTuple</a> <a href="#MaskSize"><i>maskSize</i></a>, <a href="HTuple.html">HTuple</a> <a href="#SigmaW"><i>sigmaW</i></a>, <a href="HTuple.html">HTuple</a> <a href="#SigmaD"><i>sigmaD</i></a>, <a href="HTuple.html">HTuple</a> <a href="#MinGrad"><i>minGrad</i></a>, <a href="HTuple.html">HTuple</a> <a href="#MinApparentness"><i>minApparentness</i></a>, <a href="HTuple.html">HTuple</a> <a href="#MinAngle"><i>minAngle</i></a>, <a href="HTuple.html">HTuple</a> <a href="#Subpix"><i>subpix</i></a>, out <a href="HTuple.html">HTuple</a> <a href="#Row"><i>row</i></a>, out <a href="HTuple.html">HTuple</a> <a href="#Column"><i>column</i></a>)</code></p>
<p>
<code>void <a href="HImage.html">HImage</a>.<b>PointsSojka</b>(int <a href="#MaskSize"><i>maskSize</i></a>, <a href="HTuple.html">HTuple</a> <a href="#SigmaW"><i>sigmaW</i></a>, <a href="HTuple.html">HTuple</a> <a href="#SigmaD"><i>sigmaD</i></a>, <a href="HTuple.html">HTuple</a> <a href="#MinGrad"><i>minGrad</i></a>, <a href="HTuple.html">HTuple</a> <a href="#MinApparentness"><i>minApparentness</i></a>, double <a href="#MinAngle"><i>minAngle</i></a>, string <a href="#Subpix"><i>subpix</i></a>, out <a href="HTuple.html">HTuple</a> <a href="#Row"><i>row</i></a>, out <a href="HTuple.html">HTuple</a> <a href="#Column"><i>column</i></a>)</code></p>
<p>
<code>void <a href="HImage.html">HImage</a>.<b>PointsSojka</b>(int <a href="#MaskSize"><i>maskSize</i></a>, double <a href="#SigmaW"><i>sigmaW</i></a>, double <a href="#SigmaD"><i>sigmaD</i></a>, double <a href="#MinGrad"><i>minGrad</i></a>, double <a href="#MinApparentness"><i>minApparentness</i></a>, double <a href="#MinAngle"><i>minAngle</i></a>, string <a href="#Subpix"><i>subpix</i></a>, out <a href="HTuple.html">HTuple</a> <a href="#Row"><i>row</i></a>, out <a href="HTuple.html">HTuple</a> <a href="#Column"><i>column</i></a>)</code></p>
</div>
<div data-if="python" style="display:none;">
<p>
<code>def <b>points_sojka</b>(<a href="#Image"><i>image</i></a>: HObject, <a href="#MaskSize"><i>mask_size</i></a>: int, <a href="#SigmaW"><i>sigma_w</i></a>: Union[float, int], <a href="#SigmaD"><i>sigma_d</i></a>: Union[float, int], <a href="#MinGrad"><i>min_grad</i></a>: Union[int, float], <a href="#MinApparentness"><i>min_apparentness</i></a>: Union[int, float], <a href="#MinAngle"><i>min_angle</i></a>: float, <a href="#Subpix"><i>subpix</i></a>: str) -&gt; Tuple[Sequence[float], Sequence[float]]</code></p>
</div>
<h2 id="sec_description">描述</h2>
<p><code><span data-if="hdevelop" style="display:inline">points_sojka</span><span data-if="c" style="display:none">points_sojka</span><span data-if="cpp" style="display:none">PointsSojka</span><span data-if="com" style="display:none">PointsSojka</span><span data-if="dotnet" style="display:none">PointsSojka</span><span data-if="python" style="display:none">points_sojka</span></code> defines a corner as the point of intersection of two
straight, non-collinear gray value edges. To decide whether a point of the
input image <a href="#Image"><i><code><span data-if="hdevelop" style="display:inline">Image</span><span data-if="c" style="display:none">Image</span><span data-if="cpp" style="display:none">Image</span><span data-if="com" style="display:none">Image</span><span data-if="dotnet" style="display:none">image</span><span data-if="python" style="display:none">image</span></code></i></a> is a corner or not, a neighborhood of
<a href="#MaskSize"><i><code><span data-if="hdevelop" style="display:inline">MaskSize</span><span data-if="c" style="display:none">MaskSize</span><span data-if="cpp" style="display:none">MaskSize</span><span data-if="com" style="display:none">MaskSize</span><span data-if="dotnet" style="display:none">maskSize</span><span data-if="python" style="display:none">mask_size</span></code></i></a> x
<a href="#MaskSize"><i><code><span data-if="hdevelop" style="display:inline">MaskSize</span><span data-if="c" style="display:none">MaskSize</span><span data-if="cpp" style="display:none">MaskSize</span><span data-if="com" style="display:none">MaskSize</span><span data-if="dotnet" style="display:none">maskSize</span><span data-if="python" style="display:none">mask_size</span></code></i></a> points is inspected. Only those image regions that are
relevant for the decision are considered. Pixels with a magnitude of the
gradient of less than <a href="#MinGrad"><i><code><span data-if="hdevelop" style="display:inline">MinGrad</span><span data-if="c" style="display:none">MinGrad</span><span data-if="cpp" style="display:none">MinGrad</span><span data-if="com" style="display:none">MinGrad</span><span data-if="dotnet" style="display:none">minGrad</span><span data-if="python" style="display:none">min_grad</span></code></i></a> are ignored from the outset.
</p>
<p>Furthermore, only those of the remaining points are used that belong to one
of the two gray value edges that form the corner.
For this, the so called Apparentness is calculated,
which is an indicator of the probability that the examined point actually
is a corner point. Essentially, it is determined
by the number of relevant points and their gradients. A point can only be
accepted as a corner when its Apparentness is at least
<a href="#MinApparentness"><i><code><span data-if="hdevelop" style="display:inline">MinApparentness</span><span data-if="c" style="display:none">MinApparentness</span><span data-if="cpp" style="display:none">MinApparentness</span><span data-if="com" style="display:none">MinApparentness</span><span data-if="dotnet" style="display:none">minApparentness</span><span data-if="python" style="display:none">min_apparentness</span></code></i></a>. Typical values of <a href="#MinApparentness"><i><code><span data-if="hdevelop" style="display:inline">MinApparentness</span><span data-if="c" style="display:none">MinApparentness</span><span data-if="cpp" style="display:none">MinApparentness</span><span data-if="com" style="display:none">MinApparentness</span><span data-if="dotnet" style="display:none">minApparentness</span><span data-if="python" style="display:none">min_apparentness</span></code></i></a> should
range in the region of a few multiples of <a href="#MinGrad"><i><code><span data-if="hdevelop" style="display:inline">MinGrad</span><span data-if="c" style="display:none">MinGrad</span><span data-if="cpp" style="display:none">MinGrad</span><span data-if="com" style="display:none">MinGrad</span><span data-if="dotnet" style="display:none">minGrad</span><span data-if="python" style="display:none">min_grad</span></code></i></a>.
</p>
<p>To calculate the Apparentness, each mask point is
weighted according to two criteria:
First, the influence of a mask point is weighted with a Gaussian of size
<a href="#SigmaW"><i><code><span data-if="hdevelop" style="display:inline">SigmaW</span><span data-if="c" style="display:none">SigmaW</span><span data-if="cpp" style="display:none">SigmaW</span><span data-if="com" style="display:none">SigmaW</span><span data-if="dotnet" style="display:none">sigmaW</span><span data-if="python" style="display:none">sigma_w</span></code></i></a> according to its distance from the possible corner point.
<a href="#SigmaW"><i><code><span data-if="hdevelop" style="display:inline">SigmaW</span><span data-if="c" style="display:none">SigmaW</span><span data-if="cpp" style="display:none">SigmaW</span><span data-if="com" style="display:none">SigmaW</span><span data-if="dotnet" style="display:none">sigmaW</span><span data-if="python" style="display:none">sigma_w</span></code></i></a> should be roughly between quarter and half of
<a href="#MaskSize"><i><code><span data-if="hdevelop" style="display:inline">MaskSize</span><span data-if="c" style="display:none">MaskSize</span><span data-if="cpp" style="display:none">MaskSize</span><span data-if="com" style="display:none">MaskSize</span><span data-if="dotnet" style="display:none">maskSize</span><span data-if="python" style="display:none">mask_size</span></code></i></a> to obtain a reasonable proportion of the size of the
weighting function to the mask size.
Secondly, the distance of the point from the (assumed) ideal gray value edge
is estimated and the point is weighted with a Gaussian of size
<a href="#SigmaD"><i><code><span data-if="hdevelop" style="display:inline">SigmaD</span><span data-if="c" style="display:none">SigmaD</span><span data-if="cpp" style="display:none">SigmaD</span><span data-if="com" style="display:none">SigmaD</span><span data-if="dotnet" style="display:none">sigmaD</span><span data-if="python" style="display:none">sigma_d</span></code></i></a> according to that distance. I.e., pixels that (due to the
discretization of the input image) lie farther from the ideal gray value
edge have less influence on the result than pixels with a smaller distance.
Typically, it is not necessary to modify the default value <i>0.75</i>
of <a href="#SigmaD"><i><code><span data-if="hdevelop" style="display:inline">SigmaD</span><span data-if="c" style="display:none">SigmaD</span><span data-if="cpp" style="display:none">SigmaD</span><span data-if="com" style="display:none">SigmaD</span><span data-if="dotnet" style="display:none">sigmaD</span><span data-if="python" style="display:none">sigma_d</span></code></i></a> .
</p>
<p>As a further criterion, the angle is calculated, by which
the gray value edges change their direction in the corner point. A point can
only be accepted as a corner when this angle is greater than
<a href="#MinAngle"><i><code><span data-if="hdevelop" style="display:inline">MinAngle</span><span data-if="c" style="display:none">MinAngle</span><span data-if="cpp" style="display:none">MinAngle</span><span data-if="com" style="display:none">MinAngle</span><span data-if="dotnet" style="display:none">minAngle</span><span data-if="python" style="display:none">min_angle</span></code></i></a>.
</p>
<p>The position of the detected corner points is returned in
(<a href="#Row"><i><code><span data-if="hdevelop" style="display:inline">Row</span><span data-if="c" style="display:none">Row</span><span data-if="cpp" style="display:none">Row</span><span data-if="com" style="display:none">Row</span><span data-if="dotnet" style="display:none">row</span><span data-if="python" style="display:none">row</span></code></i></a>, <a href="#Column"><i><code><span data-if="hdevelop" style="display:inline">Column</span><span data-if="c" style="display:none">Column</span><span data-if="cpp" style="display:none">Column</span><span data-if="com" style="display:none">Column</span><span data-if="dotnet" style="display:none">column</span><span data-if="python" style="display:none">column</span></code></i></a>). <a href="#Row"><i><code><span data-if="hdevelop" style="display:inline">Row</span><span data-if="c" style="display:none">Row</span><span data-if="cpp" style="display:none">Row</span><span data-if="com" style="display:none">Row</span><span data-if="dotnet" style="display:none">row</span><span data-if="python" style="display:none">row</span></code></i></a> and <a href="#Column"><i><code><span data-if="hdevelop" style="display:inline">Column</span><span data-if="c" style="display:none">Column</span><span data-if="cpp" style="display:none">Column</span><span data-if="com" style="display:none">Column</span><span data-if="dotnet" style="display:none">column</span><span data-if="python" style="display:none">column</span></code></i></a> are calculated
with subpixel accuracy if <a href="#Subpix"><i><code><span data-if="hdevelop" style="display:inline">Subpix</span><span data-if="c" style="display:none">Subpix</span><span data-if="cpp" style="display:none">Subpix</span><span data-if="com" style="display:none">Subpix</span><span data-if="dotnet" style="display:none">subpix</span><span data-if="python" style="display:none">subpix</span></code></i></a> is <i><span data-if="hdevelop" style="display:inline">'true'</span><span data-if="c" style="display:none">"true"</span><span data-if="cpp" style="display:none">"true"</span><span data-if="com" style="display:none">"true"</span><span data-if="dotnet" style="display:none">"true"</span><span data-if="python" style="display:none">"true"</span></i>. They are
calculated only with pixel accuracy if <a href="#Subpix"><i><code><span data-if="hdevelop" style="display:inline">Subpix</span><span data-if="c" style="display:none">Subpix</span><span data-if="cpp" style="display:none">Subpix</span><span data-if="com" style="display:none">Subpix</span><span data-if="dotnet" style="display:none">subpix</span><span data-if="python" style="display:none">subpix</span></code></i></a> is
<i><span data-if="hdevelop" style="display:inline">'false'</span><span data-if="c" style="display:none">"false"</span><span data-if="cpp" style="display:none">"false"</span><span data-if="com" style="display:none">"false"</span><span data-if="dotnet" style="display:none">"false"</span><span data-if="python" style="display:none">"false"</span></i>.
</p>
<h2 id="sec_attention">注意</h2>
<p>Note that filter operators may return unexpected results if
an image with a reduced domain is used as input. Please refer to the
chapter <a href="toc_filters.html">过滤器</a>.</p>
<h2 id="sec_execution">运行信息</h2>
<ul>
  <li>多线程类型:可重入(与非独占操作符并行运行)。</li>
<li>多线程作用域:全局(可以从任何线程调用)。</li>
  <li>未经并行化处理。</li>
</ul>
<h2 id="sec_parameters">参数表</h2>
  <div class="par">
<div class="parhead">
<span id="Image" class="parname"><b><code><span data-if="hdevelop" style="display:inline">Image</span><span data-if="c" style="display:none">Image</span><span data-if="cpp" style="display:none">Image</span><span data-if="com" style="display:none">Image</span><span data-if="dotnet" style="display:none">image</span><span data-if="python" style="display:none">image</span></code></b> (input_object)  </span><span>singlechannelimage <code>→</code> <span data-if="hdevelop" style="display:inline">object</span><span data-if="dotnet" style="display:none"><a href="HImage.html">HImage</a></span><span data-if="python" style="display:none">HObject</span><span data-if="cpp" style="display:none"><a href="HImage.html">HImage</a></span><span data-if="c" style="display:none">Hobject</span> (byte / int1 / int2 / uint2 / int4 / real)</span>
</div>
<p class="pardesc">Input image.</p>
</div>
  <div class="par">
<div class="parhead">
<span id="MaskSize" class="parname"><b><code><span data-if="hdevelop" style="display:inline">MaskSize</span><span data-if="c" style="display:none">MaskSize</span><span data-if="cpp" style="display:none">MaskSize</span><span data-if="com" style="display:none">MaskSize</span><span data-if="dotnet" style="display:none">maskSize</span><span data-if="python" style="display:none">mask_size</span></code></b> (input_control)  </span><span>integer <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">int</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (integer)</span><span data-if="dotnet" style="display:none"> (<i>int</i> / </span><span data-if="dotnet" style="display:none">long)</span><span data-if="cpp" style="display:none"> (<i>Hlong</i>)</span><span data-if="c" style="display:none"> (<i>Hlong</i>)</span></span>
</div>
<p class="pardesc">Required filter size.</p>
<p class="pardesc"><span class="parcat">Default:
      </span>9</p>
<p class="pardesc"><span class="parcat">List of values:
      </span>5, 7, 9, 11, 13</p>
</div>
  <div class="par">
<div class="parhead">
<span id="SigmaW" class="parname"><b><code><span data-if="hdevelop" style="display:inline">SigmaW</span><span data-if="c" style="display:none">SigmaW</span><span data-if="cpp" style="display:none">SigmaW</span><span data-if="com" style="display:none">SigmaW</span><span data-if="dotnet" style="display:none">sigmaW</span><span data-if="python" style="display:none">sigma_w</span></code></b> (input_control)  </span><span>number <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">Union[float, int]</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (real / </span><span data-if="hdevelop" style="display:inline">integer)</span><span data-if="dotnet" style="display:none"> (<i>double</i> / </span><span data-if="dotnet" style="display:none">int / </span><span data-if="dotnet" style="display:none">long)</span><span data-if="cpp" style="display:none"> (<i>double</i> / </span><span data-if="cpp" style="display:none">Hlong)</span><span data-if="c" style="display:none"> (<i>double</i> / </span><span data-if="c" style="display:none">Hlong)</span></span>
</div>
<p class="pardesc">Sigma of the weight function according to the distance
to the corner candidate.</p>
<p class="pardesc"><span class="parcat">Default:
      </span>2.5</p>
<p class="pardesc"><span class="parcat">Suggested values:
      </span>2.0, 2.2, 2.4, 2.5, 2.6, 2.8, 3.0</p>
<p class="pardesc"><span class="parcat">Restriction:
      </span><code>2.0 &lt;= SigmaW &amp;&amp; SigmaW &lt;= 3.0</code></p>
</div>
  <div class="par">
<div class="parhead">
<span id="SigmaD" class="parname"><b><code><span data-if="hdevelop" style="display:inline">SigmaD</span><span data-if="c" style="display:none">SigmaD</span><span data-if="cpp" style="display:none">SigmaD</span><span data-if="com" style="display:none">SigmaD</span><span data-if="dotnet" style="display:none">sigmaD</span><span data-if="python" style="display:none">sigma_d</span></code></b> (input_control)  </span><span>number <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">Union[float, int]</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (real / </span><span data-if="hdevelop" style="display:inline">integer)</span><span data-if="dotnet" style="display:none"> (<i>double</i> / </span><span data-if="dotnet" style="display:none">int / </span><span data-if="dotnet" style="display:none">long)</span><span data-if="cpp" style="display:none"> (<i>double</i> / </span><span data-if="cpp" style="display:none">Hlong)</span><span data-if="c" style="display:none"> (<i>double</i> / </span><span data-if="c" style="display:none">Hlong)</span></span>
</div>
<p class="pardesc">Sigma of the weight function for the distance
to the ideal gray value edge.</p>
<p class="pardesc"><span class="parcat">Default:
      </span>0.75</p>
<p class="pardesc"><span class="parcat">Suggested values:
      </span>0.6, 0.7, 0.75, 0.8, 0.9, 1.0</p>
<p class="pardesc"><span class="parcat">Restriction:
      </span><code>0.6 &lt;= SigmaD &amp;&amp; SigmaD &lt;= 1.0</code></p>
</div>
  <div class="par">
<div class="parhead">
<span id="MinGrad" class="parname"><b><code><span data-if="hdevelop" style="display:inline">MinGrad</span><span data-if="c" style="display:none">MinGrad</span><span data-if="cpp" style="display:none">MinGrad</span><span data-if="com" style="display:none">MinGrad</span><span data-if="dotnet" style="display:none">minGrad</span><span data-if="python" style="display:none">min_grad</span></code></b> (input_control)  </span><span>number <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">Union[int, float]</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (real / </span><span data-if="hdevelop" style="display:inline">integer)</span><span data-if="dotnet" style="display:none"> (<i>double</i> / </span><span data-if="dotnet" style="display:none">int / </span><span data-if="dotnet" style="display:none">long)</span><span data-if="cpp" style="display:none"> (<i>double</i> / </span><span data-if="cpp" style="display:none">Hlong)</span><span data-if="c" style="display:none"> (<i>double</i> / </span><span data-if="c" style="display:none">Hlong)</span></span>
</div>
<p class="pardesc">Threshold for the magnitude of the gradient.</p>
<p class="pardesc"><span class="parcat">Default:
      </span>30.0</p>
<p class="pardesc"><span class="parcat">Suggested values:
      </span>20.0, 15.0, 30.0, 35.0, 40.0</p>
</div>
  <div class="par">
<div class="parhead">
<span id="MinApparentness" class="parname"><b><code><span data-if="hdevelop" style="display:inline">MinApparentness</span><span data-if="c" style="display:none">MinApparentness</span><span data-if="cpp" style="display:none">MinApparentness</span><span data-if="com" style="display:none">MinApparentness</span><span data-if="dotnet" style="display:none">minApparentness</span><span data-if="python" style="display:none">min_apparentness</span></code></b> (input_control)  </span><span>number <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">Union[int, float]</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (real / </span><span data-if="hdevelop" style="display:inline">integer)</span><span data-if="dotnet" style="display:none"> (<i>double</i> / </span><span data-if="dotnet" style="display:none">int / </span><span data-if="dotnet" style="display:none">long)</span><span data-if="cpp" style="display:none"> (<i>double</i> / </span><span data-if="cpp" style="display:none">Hlong)</span><span data-if="c" style="display:none"> (<i>double</i> / </span><span data-if="c" style="display:none">Hlong)</span></span>
</div>
<p class="pardesc">Threshold for Apparentness.</p>
<p class="pardesc"><span class="parcat">Default:
      </span>90.0</p>
<p class="pardesc"><span class="parcat">Suggested values:
      </span>30.0, 60.0, 90.0, 150.0, 300.0, 600.0, 1500.0</p>
</div>
  <div class="par">
<div class="parhead">
<span id="MinAngle" class="parname"><b><code><span data-if="hdevelop" style="display:inline">MinAngle</span><span data-if="c" style="display:none">MinAngle</span><span data-if="cpp" style="display:none">MinAngle</span><span data-if="com" style="display:none">MinAngle</span><span data-if="dotnet" style="display:none">minAngle</span><span data-if="python" style="display:none">min_angle</span></code></b> (input_control)  </span><span>angle.rad <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">float</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (real)</span><span data-if="dotnet" style="display:none"> (<i>double</i>)</span><span data-if="cpp" style="display:none"> (<i>double</i>)</span><span data-if="c" style="display:none"> (<i>double</i>)</span></span>
</div>
<p class="pardesc">Threshold for the direction change in
a corner point (radians).</p>
<p class="pardesc"><span class="parcat">Default:
      </span>0.5</p>
<p class="pardesc"><span class="parcat">Restriction:
      </span><code>0.0 &lt;= MinAngle &amp;&amp; MinAngle &lt;= pi</code></p>
</div>
  <div class="par">
<div class="parhead">
<span id="Subpix" class="parname"><b><code><span data-if="hdevelop" style="display:inline">Subpix</span><span data-if="c" style="display:none">Subpix</span><span data-if="cpp" style="display:none">Subpix</span><span data-if="com" style="display:none">Subpix</span><span data-if="dotnet" style="display:none">subpix</span><span data-if="python" style="display:none">subpix</span></code></b> (input_control)  </span><span>string <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">str</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (string)</span><span data-if="dotnet" style="display:none"> (<i>string</i>)</span><span data-if="cpp" style="display:none"> (<i>HString</i>)</span><span data-if="c" style="display:none"> (<i>char*</i>)</span></span>
</div>
<p class="pardesc">Subpixel precise calculation of the corner points.</p>
<p class="pardesc"><span class="parcat">Default:
      </span>
    <span data-if="hdevelop" style="display:inline">'false'</span>
    <span data-if="c" style="display:none">"false"</span>
    <span data-if="cpp" style="display:none">"false"</span>
    <span data-if="com" style="display:none">"false"</span>
    <span data-if="dotnet" style="display:none">"false"</span>
    <span data-if="python" style="display:none">"false"</span>
</p>
<p class="pardesc"><span class="parcat">List of values:
      </span><span data-if="hdevelop" style="display:inline">'false'</span><span data-if="c" style="display:none">"false"</span><span data-if="cpp" style="display:none">"false"</span><span data-if="com" style="display:none">"false"</span><span data-if="dotnet" style="display:none">"false"</span><span data-if="python" style="display:none">"false"</span>, <span data-if="hdevelop" style="display:inline">'true'</span><span data-if="c" style="display:none">"true"</span><span data-if="cpp" style="display:none">"true"</span><span data-if="com" style="display:none">"true"</span><span data-if="dotnet" style="display:none">"true"</span><span data-if="python" style="display:none">"true"</span></p>
</div>
  <div class="par">
<div class="parhead">
<span id="Row" class="parname"><b><code><span data-if="hdevelop" style="display:inline">Row</span><span data-if="c" style="display:none">Row</span><span data-if="cpp" style="display:none">Row</span><span data-if="com" style="display:none">Row</span><span data-if="dotnet" style="display:none">row</span><span data-if="python" style="display:none">row</span></code></b> (output_control)  </span><span>point.y-array <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">Sequence[float]</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (real)</span><span data-if="dotnet" style="display:none"> (<i>double</i>)</span><span data-if="cpp" style="display:none"> (<i>double</i>)</span><span data-if="c" style="display:none"> (<i>double</i>)</span></span>
</div>
<p class="pardesc">Row coordinates of the detected corner points.</p>
</div>
  <div class="par">
<div class="parhead">
<span id="Column" class="parname"><b><code><span data-if="hdevelop" style="display:inline">Column</span><span data-if="c" style="display:none">Column</span><span data-if="cpp" style="display:none">Column</span><span data-if="com" style="display:none">Column</span><span data-if="dotnet" style="display:none">column</span><span data-if="python" style="display:none">column</span></code></b> (output_control)  </span><span>point.x-array <code>→</code> <span data-if="dotnet" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="python" style="display:none">Sequence[float]</span><span data-if="cpp" style="display:none"><a href="HTuple.html">HTuple</a></span><span data-if="c" style="display:none">Htuple</span><span data-if="hdevelop" style="display:inline"> (real)</span><span data-if="dotnet" style="display:none"> (<i>double</i>)</span><span data-if="cpp" style="display:none"> (<i>double</i>)</span><span data-if="c" style="display:none"> (<i>double</i>)</span></span>
</div>
<p class="pardesc">Column coordinates of the detected corner points.</p>
</div>
<h2 id="sec_result">结果</h2>
<p><code><span data-if="hdevelop" style="display:inline">points_sojka</span><span data-if="c" style="display:none">points_sojka</span><span data-if="cpp" style="display:none">PointsSojka</span><span data-if="com" style="display:none">PointsSojka</span><span data-if="dotnet" style="display:none">PointsSojka</span><span data-if="python" style="display:none">points_sojka</span></code> returns <TT>2</TT> (
      <TT>H_MSG_TRUE</TT>)
     if all parameters are correct and
no error occurs during the execution.  If the input is empty the
behavior can be set via
<a href="set_system.html"><code><span data-if="hdevelop" style="display:inline">set_system('no_object_result',&lt;Result&gt;)</span><span data-if="c" style="display:none">set_system("no_object_result",&lt;Result&gt;)</span><span data-if="cpp" style="display:none">SetSystem("no_object_result",&lt;Result&gt;)</span><span data-if="com" style="display:none">SetSystem("no_object_result",&lt;Result&gt;)</span><span data-if="dotnet" style="display:none">SetSystem("no_object_result",&lt;Result&gt;)</span><span data-if="python" style="display:none">set_system("no_object_result",&lt;Result&gt;)</span></code></a>.  If necessary, an
exception is raised.</p>
<h2 id="sec_references">References</h2>
<p>

Eduard Sojka: “A New and Efficient Algorithm for Detecting the
Corners in Digital Images”. Pattern Recognition, Luc Van Gool
(Editor), LNCS 2449, pp. 125-132, Springer Verlag, 2002.
</p>
<h2 id="sec_module">模块</h2>
<p>
Foundation</p>
<!--OP_REF_FOOTER_START-->
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